Vent construction for airplane fuel tanks



Feb. l, 1949. F'. E.'sNow I 2,450,368

VENT CONSTRUCTION FOR AIRPLANE FUEL TANKS Filed Aug. 5d, 1947 aflayd iJaua,

INVENTOR.

, Afro/:NEM Y Patented Feb. 1, 1949 Y f. vNT coNsTRUcTIoN Fon AIRPLANE:FUEL TANKS Floyd E. Snow, Pasadena, Calif., assigner to TechnicalCoatings, Inc., Pasadena, Calif., a corporation ofCalifornia ApplicationAugust so, 1941, seri-a1 No. 771,505

s claims.

1 e This invention relates to airplane fuelvtanks and particularly tofuel Ytanks incorporated as parts of the wing structures. 1

The airfoil surfaces of airplane wings are necessarily designed to be asfreey of, obstructions to the air stream as possible. Since theminimizing of weight is also an importantfactor, the rigidity of such`Wing structures isycommonly obtained by the aidof trusses and. otherreinforcement members in the Vinterior of the wings; and often, hollowchannel-like hat sections are attached to the interior of the platesforming the wings, and running parallel to an edge of the wingstructure.

When the interior of sucha Wing section is used as a fuel tank, and theAhat section stiieners are sealed aroundvtheir ends and edges to preventfuel from entering areas not accessible for adequate installation ofsealant, minor leaks can develop' around and into the hat sections. Theow and accumulation of fuel over a period may readily lead to dangerouslire hazards. Furthermore, thefuel may leak into the space dened betweenthe interior surface of the wing and the hat sections attached thereto.In such a conned space, the vapor pressure may reach a relatively highvalue with consequent attendant danger of aggravating the existing leaksor establishing additional ones.

It is one of the objects of this invention to reduce these hazards byensuring that the hat section spaces are vented; thus preventing anyrise in pressure.

It is another object of this invention to provide a simple and effectiveconstruction for this purpose, that can be readily installed in a fueltank.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of severalembodiments of the invention. For this purpose there are shown a fewforms in the drawings accompanying and forming part of the presentspecification. The forms will now be described in detail illustratingthe general prin ciples of the invention; but it is to be understoodthat this detailed description is not to .be taken in a limiting sense,since the scope of this invention is best dened by the appended claims.

Referring to the drawings:

Figure 1 is a sectional, pictorial view of a fuel tank incorporating theinvention, some of the parts being shown diagrammatically Fig. 2 is afragmentary, sectional view of the tank on an enlarged scale;

Fig. 3 is a view similar to Fig-2, but of a modied form of theinvention; and 1 Fig. 4 is an enlarged sectional view-of one of the ventfittings.

Y The tank for the airplane is shown as bounded by the outer wall l of awing section havinga leading edge 2. Although this outer Wall l `isshown as a continuous wall, it is tobe understood that `the usualstructural elements vto form. the wing section may be used, joinedtogether as by welding or riveting.

Running parallel with the leading edge 2 `are a number of reinforcingchannel members 3, ordinarlly termed hat sections.v These are attachedin any appropriate manner` to the'inner surface of the outer wall l,some of them being located adjacent the top of the wing section andothers at the bottom of the Wing section.: The tank compartment is denedby the wall l and the internal gir-dery plate 4, shown in Fig. l.Transverse trusses 5 having apertures-6, l, il,v etc. are Ydisposed inspaced relationship along the length of the wingstructure.Y Y Y s All ofthe hat sections 3 are of similar configuration. They extend entirelyalong the whole length of the tank and form closed spaces, such as 9, atthe top of the tank, and spaces l0 at the bottom of the tank.Appropriate sealing means, such as the putty-like seal l l (Fig. 4) maybe placed between the edges of the hat section flanges and Wall I, toreduce the likelihood of leaks from the interior of the tank to thespaces 9 and I0.

Each of the top spaces 9 is vented to the exterior of the Wing section,as by the aid of the Vents I2 through the wing section. In this Way,should there be any leaks from the interior of the tank past any edge ofthe hat sections 3, the fuel collected in these closed spaces 9 wouldnot be subject to other than atmospheric pressure. Furthermore, sincethe tank would not be entirely filled with liquid, the likelihood of anymaterial amount of fuel leaking into these upper spaces is reduced.

However, fuel may leak into the lower spaces l il in spite of allprecautions to seal these spaces. If there were no vents from thesespaces, vapor pressures would occur in these closed spaces that wouldaggravate the leak. Accordingly, provisions are made to vent each of thelower spaces l0 to the upper space 9 by the aid of vent connections thatare located Within the tank or wing section- Thus, as shown most clearlyin Fig. 2, a, number of spaces l0 may be joined by the vent connec- ItiS required merely that all of the lower spaces i I?" I0 be connected toa vented upper spacefordirectly to the upper surface the arrangementiofthe vent pipes being otherwise immaterial.

For example, in the formef Fig: 3,'fthe upper space 2| is vented, butother upper spaces 2'2"and 23 are not vented. Here, all of these threeupper spaces are in communication with the atmosphere by the aid of thevent connections 24 and 25. The vent connections to the lower spacesI0"arel`f fected by the vent connection 28, joined to theright-ghandspaces Igan'd.y by the supplemental Y vent connection 2'!jcinedtolthisvtop space-2?'.

The manner .-inwhichth'e ventpipeemay be connected is a matter ofchoice. For-example, Fignzshows one .structure to effect suchconnections?from-theventpipes to either a top or bottom space. v..'Ihus;:in Fig. 4, the hat section 3 is shown as having-a largeaperture128 at its crest covered by afriveted.arcuatefplate 291lPassingthrough the plate 29 is a nipple 3U having' 'anintegralhexagonal'sectionl 3 Iv lintermediate lthe body of the nipplez.nut 32 inside Lspacei servesto fasten thef'innerfend Aof` thenipple'in" a iuid-tiglit`-mannertofzthe'zfcover 'plate'129' A-coupling nut33engages-tne-lower end of the nipple' 3S.' It engagesaf'sleeve"34ithrough'which the vent I5 passes-andwhich-fisinfsealedcontact with the lower end `of thenipple 30;' Sincesuchpipe uniensarewell known, it1isnot necessary-to disclose furtherdetailsthereol" 1 Y f 1 fThe nut 33 is tightened suciently to hold theupper anged ends offthe sleeve 3:3 andfvent pipe 4 I6 in sealed relationto the lower end of the nipple 30.

All of the Vent pipes shown may be similarly joined and coupled.

The inventor claims:

1. In an airplane fuel tank; walls defining the tank structure;channel-,like members secured on the interior" 'f "thewllslforlreiniforcement and forming"`spacs :betweei'tli walls and themembers; at least some of the members being at the bottom wall; andmeans within the tank for venting `Athe.' said"F spaces that areadjacent the bottom Wall.

2. In an airplane fuel tank: walls defining the tank' structureschannel-like members secured ohthlint'eriorofthe Wall for reinforcementand lforming spaces between the walls and the members'thos"Spacesat thetop of the tank being vented; and means within the tank connecting allof thespaces adjacent the bottom wall to vented spaces at thetop of thetank.

" 3. Iman airpl'aine lfueltank: walls deiining the tank structure;channel-.like-ine`1r1]oerssecuredori the interior of the wallforieinforcement"and "forming spaces b'etweien'the' walls', and' theVmem- `vented; and means within the tank connecting all of the'spacesadjacent thebttom wall to vented spaces at the topf'fthetank';comprisingventing tube ontubes connecting VNthe l'lott'orn spaces with spaces.1.-.. fi r .fd s `L FLOYD SNOW- REFERENCES 'Ifile following referencesarehoif record in the fue Yor this paepi UNITED STATES PATENTS

